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| Extended ATA commands (48bit) and Sunrise IDE
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Prodatron
msx master
Berichten: 1109 |  Geplaatst: 09 November 2006, 15:29 |
Because of a discussion in the CPC scene I want to add extended ATA support in SymbOS, which increases the sector numbers from 28bit to 48bit. This will allow to access a maximum of 2TB with FAT32 instead of the current 128GB.
Can anyone help me with the following questions?
1.) where do I find a documentation how to set a 48bit LBA address with an IDE interface? I made some Google searches but without any success yet.
2.) do modern hard discs with a size of >128GB do not support normal ATA commands (28bit) anymore?
I know that already 128GB is completely oversized for a Z80 system, and that 2TB is just crazy. But because of question (2) some people are afraid, that you can't use modern hard discs anymore in the future, if you only use 28bit commands.
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Prodatron
msx master
Berichten: 1109 | Geplaatst: 09 November 2006, 20:07 |
Already found it:
http://www.t13.org/technical/e00101r0.pdf
And:
"New devices implementing this 48-bit addressing are totally backward compatible with existing
hosts and host software. The usable capacity of the device will be limited to that addressable by
the host but the device will operate normally at that capacity."
Just FYI... |
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manuel
msx guru
Berichten: 3451 | Geplaatst: 09 November 2006, 20:34 |
So, better spend some effort on SCSI support  |
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ARTRAG
msx master
Berichten: 1688 | Geplaatst: 09 November 2006, 20:47 |
I think that 128GB is sufficient for storing the whole production of MSX SW ever developed across the face of the world since 1983 to nowadays
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msd
msx professional
Berichten: 615 | Geplaatst: 09 November 2006, 21:49 |
I can make some v9990 movie files to fill it |
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manuel
msx guru
Berichten: 3451 | Geplaatst: 09 November 2006, 23:02 |
ARTRAG: very much more than enough!
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Vampier
msx addict
Berichten: 496 | Geplaatst: 10 November 2006, 00:37 |
what is the data transport rate for the MSX?
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Prodatron
msx master
Berichten: 1109 | Geplaatst: 10 November 2006, 16:26 |
The data rate is 162KB/s on the CPC (maximum), on a MSX2 it should be similiar or a little bit faster.
That means: 25.000 years for reading a 128PB harddisc 
The funny thing is, that some experts in the CPC scene are sure, that they will write applications, which need this space. |
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msd
msx professional
Berichten: 615 | Geplaatst: 10 November 2006, 16:58 |
The speed depends on the type of msx. ranging from 120KB/s to 716KB/s
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msd
msx professional
Berichten: 615 | Geplaatst: 10 November 2006, 17:50 |
Normally the IDE is quite slow on the turbo r when you compare it to novaxis SCSI. When the IDE code is completly in internal ram of the turbo r I expect it will be quite fast.
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Prodatron
msx master
Berichten: 1109 | Geplaatst: 10 November 2006, 18:37 |
Interesting! Because it is executed in the external Rom catridge? The "fast mode", where Roms are copied into the Ram, doesn't take care about the Sunrise IDE rom?
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NYYRIKKI
msx master
Berichten: 1511 | Geplaatst: 10 November 2006, 19:01 |
No, in DRAM mode only BIOS(16K), BASIC (16K), KANJI (16K) and SUBROM (16K) are copied to RAM. (=64K)
In case of SymbOS using DRAM mode is 100% waste of memory. Programs that use plenty of BIOS calls may get some small boost.
Mostly this feature is usefull for tweaking BIOS routines.
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msd
msx professional
Berichten: 615 | Geplaatst: 10 November 2006, 19:08 |
Prodratron do you use any code from the rom?. On turbo R it's always better to run stuff from internal ram.
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Prodatron
msx master
Berichten: 1109 | Geplaatst: 10 November 2006, 19:12 |
No, sorry, my question had nothing to do with SymbOS  I just was interested about the MSX in general 
Of course I already deactive the DRAM mode while booting SymbOS, and my IDE routines do not use the BIOS and run in normal Ram. |
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msd
msx professional
Berichten: 615 | Geplaatst: 10 November 2006, 19:29 |
that will probably mean it runs faster already.. Btw also use LDIR otir etc instead of multiple LDI ,OUTI on turbo r
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